/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "stdosl.h"
#include "oslutil.h"

shader node_wireframe(string bump_offset = "center",
                      int use_pixel_size = 0,
                      float Size = 0.01,
                      output float Fac = 0.0)
{
  Fac = wireframe("triangles", Size, use_pixel_size);
  /* TODO(sergey): Since we can't use autodiff here we do algebraic
   * calculation of derivatives by definition. We could probably
   * optimize this a bit by doing some extra calculation in wireframe().
   */
  if (bump_offset == "dx") {
    point dx = Dx(P);
    P -= dx;
    Fac += (Fac - wireframe("triangles", Size, use_pixel_size)) / length(dx);
  }
  else if (bump_offset == "dy") {
    point dy = Dy(P);
    P -= dy;
    Fac += (Fac - wireframe("triangles", Size, use_pixel_size)) / length(dy);
  }
}
